EQI corruption pillar, country centered and z-score standardized. For its calculation, they aggregate the individual scores (‘survey question’) to the corresponding regional level, so that each of question assessing corruption in the provision of public services is now a regional ‘indicator’. After normalizing each of corruption indicators (through z-score standardization) so that they share a common range, the corruption indicators are aggregated into two sub-pillars, called ‘experience’ and ‘perceptions. They respectively represent question items reflecting personal experience with petty corruption versus perception of corruption in various other areas. These two sub-pillars are aggregated using equal weighting.